ISLAMABAD — Pakistan said Tuesday that it had arrested a high-ranking army officer on suspicion of connections to a radical group, a rare public acknowledgment of possible ties between members of the country’s military and the extremist organizations it is battling.

The arrest comes amid rising concern that Pakistan’s military is penetrated by Islamists who are sympathetic to insurgent groups that have declared war on the state. Last month, heavily armed fighters stormed a naval base in Karachi, an attack widely suspected to have required inside help.

The arrested officer was identified Tuesday as Brig. Ali Khan, whose rank is equivalent to that of a one-star general. A Pakistani military official who declined to be quoted by name because he is not authorized to speak publicly said Khan was detained May 6 — just four days after U.S. Navy SEALs killed al-Qaeda leader Osama bin Laden during a raid in the northern garrison city of Abbottabad.

It was unclear why the arrest was made public only Tuesday, but the disclosure may be intended to signal to the United States and others in the West that Pakistan’s military leadership is committed to weeding out militant collaborators.

The military official said that Gen. Ashfaq Kayani, the army chief, personally ordered Khan’s arrest after reviewing the evidence against him and that a probe was underway to find others suspected of similar links.

Khan allegedly was working with Hizb ut-Tahrir, a radical group that calls for the overthrow of governments in Muslim lands and the installation of an Islamic caliphate. The group claims to be nonviolent but has been tied to militant organizations and is banned in Pakistan.

Khan’s wife, Anjum, called the allegations against her husband “rubbish.”

“He loves the Pakistani army more than his life, and he can’t even think of betraying the institution,” she said.

Khan had been stationed at the Pakistani army’s general headquarters in Rawalpindi. He was working in the military’s regulations department at the time of his arrest and had a spotless record, the official said.

“Khan’s family has been associated with the Pakistan army for three generations,” he said. “His father was a junior commissioned officer; his younger brother is a colonel in the army; and his son and son-in-law are also serving as captains in the army.”

The report of Khan’s arrest follows the disclosure last week that Pakistan had detained for questioning a number of Pakistanis who had helped the CIA gather information about bin Laden’s compound in Abbottabad. Among those picked up was a serving army major.

Those arrests became yet another friction point in the relationship between the United States and Pakistan, which is at its lowest level in a decade.

A survey of Pakistani public opinion released Tuesday by the Pew Research Center’s Global Attitudes Project showed that a significant majority of Pakistanis — 63 percent — disapprove of the raid that killed bin Laden. Overall, 12 percent of Pakistanis said they had a favorable view of the United States, compared with 17 percent last year.

The decline in support for the United States has been accompanied by a marked erosion in backing for the Pakistani army’s campaign against extremists. Thirty-seven percent of Pakistanis said they support that effort, compared with 53 percent two years ago. Large majorities of Pakistanis want the United States to pull its troops from neighboring Afghanistan, and nearly seven in 10 say they see the United States as an enemy.

“It is well nigh impossible to be pro-American in Pakistan,” said Tariq Fatemi, a former top Pakistani diplomat who served in the United States for 11 years. “And American policies in Pakistan haven’t helped matters.”

Hussain is a special correspondent.

by Griff Witte

ISLAMABAD — Pakistan on Tuesday said it had arrested a high-ranking army officer for alleged connections to militant groups, a rare public acknowledgment of possible ties between this country’s military and the organizations it is battling.

The arrest comes amid rising concern that Pakistan’s military is penetrated by Islamists who are sympathetic to insurgent groups that have declared war on the state. Last month, a naval base in Karachi was stormed by heavily armed fighters in an attack that was widely believed to have required inside help.

The arrested officer was identified Tuesday as Brig. Ali Khan, whose rank is equivalent to that of a one-star general.

A Pakistani military official who declined to be quoted by name said the officer had been stationed at the Pakistani military’s general headquarters in Rawalpindi. He was working in the military’s regulations department at the time of his arrest.

Military officials said Khan was being questioned, but did not provide details on which militant groups he is suspected of helping or whether he had been linked to a specific attack.

Tuesday’s reported arrest follows the disclosure last week that Pakistan had detained for questioning a number of Pakistanis who had helped the CIA gather information about Osama bin Laden’s compound in the northern city of Abbottabad.